Platini said he would rather remain head of the European football federation than challenge Blatter.
"This is the decision I have made. It is about what I want to do with Uefa, " he told reporters.
FIFA has been plagued with numerous corruption scandals, especially during the time of the World Cup in Brazil. Many critics say Blatter is complicit in this corruption and fuels the problem.
Platini made it clear he did not intend to bad mouth FIFA or its leadership. He said his goal is to help FIFA shed its unflattering reputation.
"I know that some of you were expecting me to attack FIFA today, one way or another. That is not my goal here. We want a FIFA that works better. We want a FIFA with more transparency, more solidarity and a FIFA that is more respected by those who love football," said Platini.